Such a dynamic vibration damper (more commonly referred to as a dynamic absorber) is described in the specification of U.S. Pat. No. 4,842,116. Its dimensions are so chosen that it acts to absorb vibrations in a frequency range around the resonant frequency of the system in which the clutch is fitted. In the above mentioned U.S. patent specification, the dynamic absorber is attached to the hub, and includes a secondary plate which is mounted coaxially through a bearing on the reaction plate, so as to be rotatable with respect to the latter. The dynamic absorber further includes a radial support plate which is also attached to the hub, and which carries a friction liner that is arranged to cooperate with the secondary plate. In addition, in order to improve damping still further, circumferentially acting resilient means are arranged to act between the reaction plate and the secondary plate. All of this has the effect of complicating the manufacture of the reaction plate of the clutch, and increases the number of components of the clutch.